Air cannon manifold

ABSTRACT

An apparatus for cleaning deposits from the interior surfaces of an industrial vessel, such as a kiln. The apparatus utilizes an air cannon manifold for selectively directing and venting a high volume of pressurized fluid to any one or more of a plurality of access ports defined in the vessel whereby the pressurized fluid is directed at the deposits to prevent them from adhering and accumulating on the walls of the vessel. A controller is provided to permit selection of a desired exhaust port for directing the pressurized fluid to the access ports and for sequencing an inlet valve in cooperation with a desired exhaust port.

FIELD OF THE INVENTION

The instant invention relates to air cannons used for cleaning andpreventing the buildup of deposits on the walls of industrial vessels,such as kilns used in the cement and paper industries. Moreparticularly, the instant invention relates to a manifold forselectively directing the blast from an air cannon to any one of aplurality of ports of an industrial vessel for removing and preventingthe build up of material deposits therein.

BACKGROUND OF THE INVENTION

In industrial vessels, such as cement, wood or paper kilns, and theirassociated structures, the accumulation of particulate deposits on theinner linings of these vessels is a recurring problem. Buildup ofdeposits in areas such as preheater and riser ducts can choke off feedpipes and cyclones and greatly affect the efficiency and productionperformance of the vessel, even to the point of causing unscheduledshutdowns. If deposits are permitted to accumulate the high temperaturestypically encountered in vessels, such as kilns, will cause the depositsto become encrusted on the kiln's interior surfaces. The precisecharacteristics of the buildup in these vessels may vary from plant toplant, the process employed, and can even vary from hour to hour withinthe same plant or process.

Usually, the buildup begins sticking to the walls of the vessel liningwith the consistency of talcum powder. Routine cleaning of the depositsis a preferred method of addressing the problem such that the depositsare removed before significant accumulation and encrustation occurs.

Air cannons have long been an accepted method for routine cleaning ofvessel walls and maintaining material flow in many industrialapplications. While there are many different configurations of aircannons, the principle of operation for all air cannons is the same. Alarge volume of air is exhausted in a short period of time through aaccess port in the vessel wall, creating a powerful burst of air whichdislodges particulate material that has adhered to the internal wall ofthe vessel. The various configurations of air cannons are generallydifferentiated based on their air discharge velocity and the design ofthe inlet seal for the associated air reservoir. However, each of thevarious air cannon configurations in use utilize a separate airreservoir as part of an air cannon attached to the particular vesselaccess port. This configuration poses many problems to those in theaffected industries.

The first concerns the installation costs associated with independentlymounted air cannons. For each air cannon in the system, a separate airreservoir incurs the added cost of purchasing and maintaining thereservoir as well as installation costs associated with routing thenecessary air lines to charge each reservoir and additional wiringactivate the individual air cannons. In some instances, attempts toavoid these installation costs have been made whereby an air cannonassembly is moved from access port to access port to clean therespective areas of the vessel. While saving on installation costs, thispractice incurs its own costs in that an employee is required toreposition the air cannon to a desired access port.

A second concern is the space requirements for installing and operatingindividual air cannons with an integrated air reservoir. Traditional aircannons with their individual air reservoirs require a substantialamount of space to install and once installed they present an obstaclefor the operators working around the particular vessel.

Third, the typical air cannon is mounted in close proximity to thevessel, and most are mounted directly to the vessel. Usually theprocesses within the vessel generate a substantial amount of heat andconsiderable particulate debris. In these harsh environments,traditional air cannons frequently experience premature wear and failureof internal components, particularly in its valve assemblies.

In many instances the valves used to control the flow of air from thereservoir require the maintenance of a pressure differential within thevalve body. In order to maintain this pressure differential withinacceptable tolerances, the rate at which the reservoir may be charged isrestricted such that subsequent firing of the cannon is delayedconsiderably. Moreover, because the restriction in the reservoir'scharging rate, exacerbates the deleterious effects of any leaks whichmay be present in the system.

SUMMARY OF THE INVENTION

The air cannon manifold of the present invention addresses theseproblems in the industry by providing an air cannon manifold thatpermits a plurality of access ports to be serviced by a single airreservoir, providing a reliable cost effective solution to theaforementioned problems. First, it reduces installation costs byeliminating the requirement for a separate air reservoir at each aircannon portal. By eliminating the requirement for a separate airreservoir, additional savings are realized at initial installation byeliminating the requirement to install a separate air line to chargeeach separate air reservoir.

Second, by eliminating the requirement for an individual air reservoirat each air access port, the initial space requirements may be reducedfor new installations employing the air cannon manifold of the presentinvention. Similarly, modification of existing installations toincorporate the air cannon manifold will permit reclamation of valuablework space previously occupied by the individual air reservoirsservicing the existing air cannon ports. In both instances, obstructionsin close proximity to the vessel are eliminated, permitting workersaround the vessel a safer work environment.

Third, the air cannon manifold of the present invention further permitsthe working components of the system, such as its valves and sensors, tobe positioned away from the high temperatures and debris generated bythe vessel, resulting in improved reliability and extending the servicelife of the components and the system.

Finally, the air cannon manifold of the present invention enables rapidcharging of the reservoir to permit a single reservoir to service aplurality of cleaning ports or to permit successive firing into anyselected cleaning port.

BRIEF DESCRIPTION OF THE DRAWINGS

The system and methodology of the present invention are depicted in theaccompanying drawings which form a portion of this disclosure andwherein:

FIG. 1 is a perspective view of an air cannon manifold and an airreservoir;

FIG. 2 is a side view of an air cannon manifold;

FIG. 3 is a perspective view of the air cannon manifold from an inputside, with an actuator removed to show an exhaust actuator bore;

FIG. 4 is a partial sectional view of an exhaust valve;

FIG. 5 is a partial sectional view of an inlet valve;

FIG. 6 is a partial sectional view of an inlet valve and exhaust valvein their open position;

FIG. 7 is a schematic diagram for sequentially selecting an exhaust portto be serviced by the air cannon manifold; and

FIG. 8 is a schematic diagram for monitoring and signaling alarmconditions of the air cannon manifold.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings for a clearer understanding of the invention,it may be seen that a preferred embodiment of the invention contemplatesa single air reservoir 11, providing a high volume pressurized airsource for an air cannon system, connected to the air cannon manifold 10via an inlet duct 12 attached to an inlet port 20. A plurality ofexhaust ducts 13 interconnect exhaust ports 30 of the air cannonmanifold 10 with the access ports of an industrial vessel, such as akiln and its associated structures.

The air cannon manifold 10 may be seen in greater detail in FIGS. 2-6.As depicted, air cannon manifold 10 comprises a housing 14, defining aplenum therein. An inlet port 20 extends through a first wall 15 inhousing 14 and receives high volume pressurized air from a source suchas a pressurized air reservoir 11 via an inlet duct 12, such as theelbow connector shown in the drawings. Inlet duct 12 may be a pipe orsimilar conduit and may be bolted to manifold 10 through a flange 17, orany suitable attachment means. An inlet valve 21 is provided to controlthe flow of air from reservoir 11 to manifold housing 14 by selectivelyopening and closing inlet port 20.

In the embodiment shown, inlet valve 21 is best seen in FIGS. 5 and 6,and comprises an inlet valve actuator 22, such as a pneumatic cylinderor the like attached to second wall 16 of manifold housing 14 an adapterplate 18 and opposing inlet port 20. An inlet actuator shaft 23, isextensible through an inlet actuator bore 24 defined in the second wall16 of manifold housing 14 and closed by plate 18. An inlet valve seal 25is attached to a distal end of inlet actuator shaft 23, and isselectively positioned by inlet valve actuator 22 for sealing engagementwith an inlet seat 26, defined on an interior face of first wall 15.Preferably inlet actuator bore 24 will be dimensioned to be larger thaninlet valve seal 25, to facilitate removal of inlet valve 21 forservicing or replacing this component.

Air cannon manifold 10 further defines a plurality of exhaust ports 30in a second wall 16 of housing 14. Exhaust ducts 13 are connected toexhaust ports 30 to communicate the high volume air released into themanifold 10 to a corresponding access port in vessel. Exhaust ducts 13may be a pipe or similar conduit and may be bolted to manifold 10through an exhaust flange 18, or any suitable attachment means. Anexhaust valve 31 is provided for each exhaust port 30 to control theflow of air delivered by manifold 10 to a desired access port in vesselserviced by the air cannon. Exhaust valves 31 are selectivelypositionable to open and close their associated exhaust ports 30. Asbest depicted in FIGS. 4 and 6, exhaust valves 31 comprise an exhaustvalve actuator 32, such as a pneumatic cylinder, attached to housingfirst wall 15 and opposing their respective exhaust ports 30. An exhaustactuator shaft 33, is extensible through an exhaust actuator bore 34defined through first wall 15. Exhaust valve seals 35 are attached tothe distal ends of exhaust actuator shafts 33 and are selectively urgedagainst exhaust port seats 36 by exhaust valve actuators 32. As with theinlet valve 21, exhaust actuator bore 34 is preferably dimensioned to belarger than exhaust valve seal 35 to facilitate removal of exhaustvalves 31 for servicing or removal of these components. A protectivering 43 may also be attached to an inner surface of first wall 15coaxial with actuator bore 34, and extending inwardly therefrom, suchthat upon opening of exhaust valve 31, exhaust valve seal 35 may beretracted into ring 43 to avoid exposure to the high velocity airexperienced within housing 14 upon opening inlet valve 21. Each exhaustvalve 31 is independently controllable to permit selective routing ofthe air blast to a desired access port in the vessel to clean therespective areas of the vessel walls based on the vessel's operatingconditions.

We have found a preferred configuration for inlet seal 25 and exhaustseals 35. According to our preferred embodiment, shown in FIGS. 4 and 6,seals 25 and 35 comprise a disk portion 41, extending from and coaxialwith a chamfered disk portion 42. Cylindrical disk portion 41 has adiameter smaller than that of the inner diameter of the respective inletport 20 or exhaust port 30 to facilitate positive alignment of the seals25, 35 in the respective ports 20, 30. The chamfered disk portion 42 hasa diameter greater than disk portion 41, and provides for sealingengagement with the respective valve seat 26, 36. More preferably,chamfered portion 42 is made of a resilient material to improve itssealing engagement as it is urged against the valve seat 26,36.

Our preferred embodiment inlet actuator 22 and exhaust actuator 32 aremounted with their operative mechanisms external to manifold housing 14.This arrangement provides the advantage of permitting ready access tothe actuators 22, 32 for routine inspection, maintenance and servicing.This arrangement also provides an advantage in that the positioning ofthe operative mechanisms avoids exposure to the large pressuredifferentials encountered within manifold housing 14 during cannonfiring sequences.

Having thus described an exemplar of our air cannon manifold, itspreferred method of operation will be described. A typical single dutycycle, for the air cannon manifold comprises the steps of sealing inletport 20, charging the air reservoir 11 with air from a pressurized airsource, opening a desired exhaust port 30, and opening inlet port 20 topermit venting of the pressurized air form reservoir 11 to the desiredaccess port on the vessel to be cleaned. This process may be controlledeither manually or automatically. A schematic diagram for a controller50 directing sequential firing of a three port air cannon manifold isshown in FIG. 7.

As may be seen in FIG. 7, the sequential firing cycle is initiated atII, which initiates an air reservoir 11 charging cycle, B02 through Q6,and exhaust port 1 activation cycle, B09 through Q2. The exhaust port 1activation cycle delays opening of a first exhaust valve 30 (normallyclosed) for sufficient time to permit completion of the air reservoir 11charging cycle. It should be noted that by maintaining the exhaustvalves 30 in the normally closed position we can significantly reducethe deleterious effects of any back draft from the vessel that may carryparticulates or high temperature air into manifold housing 14. Oncesufficient time has elapsed to charge air reservoir 11, the firstexhaust valve 30 is activated and is held open for a sufficient durationto permit completion of the inlet valve firing sequence, B04 through Q1.Upon activation of the inlet valve firing sequence, inlet valve 20 isopened, permitting the rapid venting of the pressurized air in airreservoir 11 through air cannon manifold 10, first exhaust port 30 andits associated exhaust duct 13, to the desired access port on the vesselto be cleaned. Completion of the first exhaust valve 30 activationsequence Q2, resets the air reservoir charging sequence and initiatesactivation of the cycle for a second exhaust port 30, which proceeds inlike manner to that described for the first exhaust port cycle. Itvaries from the first exhaust port cycle in that signal Q3 resets thefirst exhaust port cycle so that first exhaust valve 30 is maintained ina closed position. A third exhaust port 30 is activated in like mannerand restarts the sequenced firing cycle.

We have found that when a pneumatic actuator is used for the inlet valveactuator 22 and that actuator is reliant on the same air source that isused to charge reservoir 11 it is desirable that the charging ofreservoir 11 be delayed while inlet valve 21 is being closed to ensurethat sufficient pressure is available to reliably activate inlet valveactuator 22 for sealing inlet port 20. This may be accomplished bytemporarily closing a valve to block the communication of thepressurized air source to reservoir 11 for sufficient time to permit theclosure of inlet valve 21. The temporary interruption of airflow toreservoir 11 also facilitates alignment of inlet valve seal 25 asresidual air flow through inlet port may cause misalignment of inletvalve seal 25.

Automatic control of the air cannon manifold 10 may also be provided bymonitoring process specific variables, such as temperature, oxygencontent, or the like, that would indicate particulate accumulation atany particular location within the process vessel. In this circumstance,the blast cannon manifold controller 50 would be specifically targetedto remedy particulate accumulations based on the indications of theparticular process specific variable, thereby improving the efficiencyand efficacy of the blast cannon system in maintaining the cleanlinessof the process vessel.

In addition, as shown in FIG. 8, the blast manifold controller 50 mayalso provide notification of user determined alarm conditions within theair cannon manifold 10 or air cannon system or vessel process that maypotentially impact the safety or efficiency of the process for which theair cannon is employed.

It is to be understood that the form of the invention as shown herein isa preferred embodiment thereof and that various changes and thatmodifications may be made therein without departing from the spirit ofthe invention's scope as defined in the following claims.

1. An air cannon manifold comprising a housing defining a plenumtherein, an inlet port defined in a wall of said housing, said inletport receiving a pressurized fluid source in communication with saidinlet port, an inlet valve selectively positionable to open and closesaid inlet port, a plurality of exhaust ports defined in said wall ofsaid housing, and a plurality of exhaust valves selectively positionableto open and close said exhaust ports, whereby said pressurized fluid maybe communicated via said exhaust ports and exhausted to a selectedaccess port in a vessel to be cleaned of deposits.
 2. The air cannonmanifold of claim 1 wherein said housing is substantially boxlike. 3.The air cannon manifold of claim 1, wherein said housing issubstantially spherical.
 4. The air cannon manifold of claim 1 whereinsaid inlet valve further comprises an inlet valve actuator attached tosaid housing, said inlet valve actuator having an extensible inletactuator shaft, and an inlet valve seal attached to a distal end of saidactuator shaft, wherein said inlet actuator shaft urges said inlet valveseal in sealing engagement with said inlet port.
 5. The air cannonmanifold of claim 4 wherein said inlet valve actuator is attached to anexternal wall of said housing, and said inlet actuator shaft isextensible through an inlet actuator bore defined in said housing. 6.The air cannon manifold of claim 4, wherein said inlet valve sealfurther comprises a disk portion, extending from and coaxial with achamfered disk portion, said disk portion having a diameter smaller thansaid chamfered disk portion.
 7. The air cannon manifold of claim 6,wherein said disk portion has a diameter les than an inner diameter ofsaid inlet port.
 8. The air cannon manifold of claim 7, wherein an outersurface of said chamfered disk portion is comprised of a resilientmaterial.
 9. The air cannon manifold of claim 1 wherein said exhaustvalve further comprises an exhaust valve actuator attached to saidhousing, said exhaust valve actuator having an extensible exhaustactuator shaft, and an exhaust valve seal attached to a distal end ofsaid actuator shaft, wherein said exhaust actuator shaft urges saidexhaust valve seal in sealing engagement with said exhaust port.
 10. Theair cannon manifold of claim 9 wherein said exhaust valve actuator isattached to an external wall of said housing, and said exhaust actuatorshaft is extensible through an exhaust actuator bore defined in saidhousing.
 11. The air cannon manifold of claim 9, wherein said exhaustvalve seal further comprises a disk portion, extending from and coaxialwith a chamfered disk portion, said disk portion having a diametersmaller than said chamfered disk portion.
 12. The air cannon manifold ofclaim 11, wherein said disk portion has a diameter less than an innerdiameter of said exhaust port.
 13. The air cannon manifold of claim 11,wherein an outer surface of said chamfered disk portion is comprised ofa resilient material.
 14. The air cannon manifold of claim 1 furthercomprising a controller, wherein said controller provides a signal tosaid inlet valve and said exhaust valve and said inlet valve and exhaustvalve are selectively positionable responsive to said signals.
 15. Theair cannon manifold of claim 14, wherein said controller provides saidsignal at timed intervals.
 16. The air cannon manifold of claim 14,wherein said controller provides said signal responsive to a processvariable.
 17. A method of controlling an air cannon manifold associatedwith a kiln, said air cannon manifold comprising a housing defining aplenum therein, an inlet port defined in a wall of said housing, saidinlet port receiving a high volume pressurized fluid from a reservoircommunicating with said inlet port, an inlet valve selectivelypositionable to open and close said inlet port, a plurality of exhaustports defined in said wall of said housing, and a plurality of exhaustvalves selectively positionable to open and close said exhaust ports,said method comprising the steps of: a. closing said inlet valve to sealsaid inlet port, b. charging said reservoir with a high volume ofpressurized fluid, c. opening an exhaust valve of a selected exhaustport, d. opening said inlet valve to vent a portion of said high volumepressurized fluid from said reservoir through said air cannon manifold.18. The process of claim 17, further comprising the step of interruptingfluid flow to said reservoir while closing said inlet valve.
 19. Theprocess of claim 17, wherein the step of closing said inlet valvefurther comprises signaling said inlet valve to maintain said seal for aspecified time.
 20. The process of claim 17, wherein the step of openingan exhaust valve, further comprises signaling said exhaust valve toremain open for a specified time.
 21. The process of claim 17, whereinthe step of opening said inlet valve further comprises signaling saidinlet valve to close after a specified time.
 22. A method of controllingan air cannon manifold associated with an industrial apparatus having aplurality of access ports for cleaning said apparatus by use ofpressurized fluid, said air cannon manifold comprising a housingdefining a plenum therein, an inlet port defined in a wall of saidhousing, said inlet port receiving a high volume pressurized fluid froma reservoir communicating with said inlet port, an inlet valveselectively positionable to open and close said inlet port, a pluralityof exhaust ports defined in said wall of said housing in fluidcommunication with said access ports, and a plurality of exhaust valvesmounted to said manifold and selectively positionable to open and closesaid exhaust ports, said method comprising the steps of: a. closing saidinlet valve to seal said inlet port, b. charging said reservoir with ahigh volume of pressurized fluid, c. opening an exhaust valve of aselected one of said plurality of exhaust ports, d. opening said inletvalve to vent a portion of said high volume pressurized fluid from saidreservoir through said air cannon manifold, and, e. iterativelyrepeating said sequence to vent said pressurized fluid throughadditional selected ones of said plurality of exhaust ports.
 23. Themethod as defined in claim 22 wherein said plurality of exhaust portsare normally closed during charging of said reservoir.
 24. The method asdefined in claim 22 wherein said each of said plurality of exhaust portsare sequentially individually opened during subsequent iterations toprovide cleaning to different regions of said industrial apparatus. 25.The method as defined in claims 22 wherein said industrial apparatus ismonitored for conditions indicating desirability of fluid cleaning andsaid monitoring is used to selectively open said exhaust ports.